1 Human development is the scientific study of processes of change and stability.  The scientific study of human development began with studies of childhood during the nineteenth century.
verb (used with object), cultivated, cultivating. 1. to prepare and work on (land) in order to raise crops; till. 2. to use a cultivator on. 3. to promote or improve the growth of (a plant, crop, etc.) by labor and attention.
A cultivator is any of several types of farm implement used for secondary tillage. One sense of the name refers to frames with the teeth that pierce the soil as they are dragged through it linearly. Another sense refers to machines that use rotary motion of disks or teeth to accomplish a similar result. The rotary tiller is a principal example. Cultivators stir and pulverize the soil, either before planting or after the crop has begun growing. Unlike a harrow, which disturbs the entire surface o